This is a continuation of application Ser. No. 766,287, filed Feb. 7, 1977, now abandoned which is a division of application Ser. No. 630,792, filed Nov. 11, 1975, and now U.S. Pat. No. 4,069,249, granted Jan. 17, 1978.
This invention is in the field of chelating compounds and chelates of said compounds with metallic ions including iron ions, copper ions, cobalt ions, manganese ions, chromium ions, nickel ions, zinc ions, cadmium ions, molybdenum ions, lead ions, and the like.
More particularly this invention is in the field of; (I) a chelating agent (chelating compound) having the formula ##STR4## in which R.sub.1 through R.sub.6, M.sub.1 through M.sub.4, Z, and X.sub.1 through X.sub.4 are defined in the Summary of this invention, infra; and (II) chelates of said chelating agent with metallic ions including iron(III) and iron(II) ions.
The following U.S. Patents teach chelating compounds and chelates which are of interest:
______________________________________ U.S. Pat. No. Class Inventor(s) ______________________________________ Re. 23,904* 260/518 Bersworth 2,624,757 260/518 Bersworth 2,624,760 260/519 Bersworth 2,824,128 260/519 Dexter 2,967,196 260/507 Kroll et al 3,038,793 71/1 Kroll et al 3,110,679 252/152 Rubin 3,632,637 260/519 Martell 3,742,002 260/439R Ohlson et al 3,758,540 260/439R Martell 3,780,099 260/534E Scanlon et al 3,780,100 260/534E Scanlon et al ______________________________________ *Re. 23,904 is a reissue of U.S. Pat. No. 2,624,757